Paper-coating composition and method of making the same.



i To all 'whom 'it may concern: l

v ofthe invention, such as will enable others I Imre f D STATE s NTeuries. `.linnnrw A', minnaarL ALAs-sraivor. 'ro cass-1N contraluzloraunarca, or New roux, n. La consonancia or .Jansma rarmcoarrnoconnosrrroir annmnrnon or'muxrno run sama I ""Sipecigcaton qf'LettersPatent. y Patented J une 8, 1915'. l Appunti@ med my s,-1s1'1.. semina.maso.

Noma-wing.;

v v mentof the amount of water asv 'y Be it known that I, ANDREW DURHAM,'the dissolving qmedium for the modifying a citizen of the UnitedStates, residing at. agent, L e. an amount sufficient to .bring theBainbridge, county o Chenango,"State of modifying agent into intimatecontact with NewYork, have invented certain-new and the individualstarch granules throughout useful Improvements in PaperfCoating. themass; I then drythe mass'until'it has Compositions Aand Methods ofMaking `the y'been brought back .to substantially the con- Same; and I'do hereby declarethevfollowf dition of dryness 'of the original starch,

ingto bea full, clear', and exactY description which usually containsfrom 9% to 10% by weight omoisture. The drying operation is preferablyconducted n 'vacuo and at a temperature insu-cient to break up thestarch granules, and the modifying' action of the'acid. or itsequivalent is continued,`v under the stimulating effect of theexisting`skilled in theart to which'itappertains to e v make and uselthe same. A

In Letters l-fatent ofthe United States,

grantedto Henry V. Dunham and myself,

pNo. 1,053,719, under date of February 18,

1913, we have described and claimed cer# tain'v new and usci-ulimprovements in tle treatment ofstarch to'adapt it vfor use in thecoating of paper. In'the practice of temperature conditions prevailing-ein the' vacuum drier, 'until arrested at a sta'gefcor responding to lthe viscosity contemplated for ultimateincorporation with the ymineralbase. In order to thus arrest the modification and to positively insureagainst its ref" currencein the mass, .I employ an alkaline re--a'gentofany suitable kind andv which f5 saidimprovements- We employ oxalic' acidfoi-,the modification .of the starch and arrest'y the modication at. astage whiclrwil adapt the resulting lproduct for Asubsequent admx# l'ture vvvd-tha suitable nnera'l base or filler to producgacoating onpaperwhichv ,will be' strongly'adhesivetothe paper.r` i

My `P1. ,lit inver; is based, broadly, uPolli .the 'dlseoel'y 4thatbytheaddition of casein, as described, to Starch modifiedi oir'-eli'anged 5bythe actionV of oxalic Y acid or anequivalentfhydrolyzing ormodi! fying agent), theV mieaiion of the starchV being arrested at a'-stage which will adapt the resulting' product for subsegilent admixturewith` a mineral base or er to pro! duce `a coating on paper, thecomposition so c 'produced will be of a thinowing consistw practised, inthe coating Aoi ency and may lbealietl to' thepaper umforrnly,smoothly'a' tenaeiously and withoutv leaving brush the 'finishedSurface, and when; strongly adhesive-to thepsperz e' f- In aal-)referredpmfi army intenties,

vooutei'nplai'u-y the'v mmlfml' 011iv sbstalltr-` transportation as anjarticleygffmnu acture Y sale; lalthough, as'willrhereinafte'r moreappear, the invexitiom broadly conside-1' (paper Without the productionof an interme 'ate prodfg Y Inthe preferred first treat the starchwithout up' the starch granules and witlif-the.employ- ,is of such avcharacter'that it vmay added tol the acidulated modied starch will lmaybe,;" for instance, an alkali.v which When` j act as ameutralizing agentand will so adapt 5 -ammonia lpern'J/cs of the complete neutralizationlof-the mass with the production of a neutral salt and the volatilizationof any ex cess of ammonia employed. To produce the; dry product, theneutralized modied starch may then be 'dried in any usual manner. To

the'dry roduct just described there is then added vely ypowdered caseinwhich has alkali. i orderto more ully describe-the detaiis ofa typicalexample ofthe practice of my invention for thsep'roduetion of a dryprodpraeti runder, preferred Vconditions; G Y starch to modied areadmiredwith 'a solution consi 4eme; of axane crystals fin .m-

1,00 first received an addition of some suitable alkaline material,suchv as an 1'06 I will now gvean oi its com.r

' been practically-.exp

'200 lbs. of water,l and the mixture is* stirred in' an -apparatus ofthe type of a dough niixeror the like until thesolntion has beenuniformly and. homogeneously incorporated with the starch granules.' Atthe conclusion of the lmixing operation, the starch mass will haveabsorbed. the solution ofoxalic acid and will befsuiiciently damp 4sothat, if a portion of it is squeezed in the hand, it Ywill havesuiicient' cohesion to barely ball or cake together, showing the uimprint of the fingers. In some instances, a

greater or less amount of oxalic acid may be employed, but the amount ofoxalic ,acid

should preferably not fall below from to lbs. in any case in a mixtureofthe relative quantities ofstarch and'water -above noted. So also, alarger proportion of water may be used but, in that event,av-correspending additional burdenfwould be im.

posed'upon the dryin apparatus employed. in the next stage oft emanufacture. Thei adampened mass of starch, hom'ogeneously admixed withthe solution of oxalic acid,is. next introduced into a rotary Avacuumdrier, which is preferred'for the reason that,I it insures the uniformconduct of the processi during this period, and particularly because Ait permits the speeding up of the drying operation, at a temperaturewhich is safely below the limits of the temperature which would break upthe starch granulesand con- The rotaryp vert the mass into a. paste.vacuum drier -that I- preferfor the purpose would be provided withV asteam jacket, which may conveniently be supplied Vwithv steam at say 20lbs. lsuperatmo'spheric pressure, corresponding to a temperature of 40'prefer to maintaina vacuum of about 259 F. Within the vacuum drier, Isay 20 inches, sothat the internalL temperature durv ing the dryingoperationshallbe 'corref I s'pondingly1 the brea g up ofthe starchgranules. It is found. that at the termination of a period .varyingsomewhat with the prevailing conf ditions, but usuall about one and onehalf hours, and While t e drier is rotating 'at an *average speed offrom five to six revolutions -per minute, the water of solution haselled, leaving the starch .with about its'original content of moisture,

say 9 to 11%'1 b wei ht. UnderAthe-'con- .tinued :action o the eat, the'oxalicacid exerts a continued modiying action uponthe starch,and, atthis stageof the operation, extreme Vcare must be taken tof'super- .visevand-testv its progress, so that 1t may neither fall short/of nor exceedthe limits7 necessary for thef'ultimate result., To this end, -from timetol time, the. rotation of the drier is interrupted and a sam le ofthecon.-

tents is taken and quickly teste for viscosity.

, A suitable viscosity test which I have used with successll' resultsconsists'in comparing restricted well below the limit off the rate offlow of afstandard solution of they test' sample, neutralized andboiled, as hereinafter specified, with the rate Aof lflow of waterthrough a-burette, delivering 58 c..c, of water in a period of half aminute. The

, burette has alengthof 36inches, and an internal diameter of gths of aninch. To 100.-k giams Iof the'dry starch is first added 400 gramsofColdwater.` The Water and starch. are stirred well together andsufficientam-.` monia of 26 Baum is added to' make the solutionalkaline.,v Themixture is heated to between 185 F. and' 190,.F. therebybreakecold 'water is added to produce a volumev of about 970 c. c. ofthe mixture at a temperaling up the'starch granules. .Then enough Yture'- of 100 F.- In the meantime, vthe ..burette has been broughtto thesamev tem-v peratureand the burette is lled withthe solution' and itsrate .of flow tested.- A'-When" the-test of any particularv sample,(withdue- Y allowance orthe time" occupied by the making of the test)indicates that the starchin l the drum will respond to a viscosity iiow*of from 40e. c., orjthereabout, tofl c. c. .or thereabout forprinting-and ordinary litho;- graphic workfI havej employed a viscosityiiow corresponding to 45 c. c. or for the higher' grades' oflithographie work, a-viscosity flow -of40 c. c.. or thereabout) in halfa minute 'from-the buretteemployed,

the rotation, of the drum 4is interruptedl and' its contents are`*immediately discharged into a-second mixing apparatus containing 40.

lbs.- of 26.ammonia in -200 lbs. of water. The massis at once viorou'sly stirred, so as ico to interrupt the-modi ing action bythoroughly neutralizing the acid.- Thereupon,

dried in any convenient manner, as, vforinheated in a drying tunnel orthe like.

' the neutralized'mass of modified starch is stance, by being placed inshallow trays and A.

'Itwill usually Vbe found desirable,',beiore i placing the neutralizedmassl in the trays" to pass it through a breaker for-the purpose ofbreaking up anylurnps that may-.have formed, so that 'thedryingoperationmay proceed with-corresponding promptness and.uniformity. It is unnecessary to take special precautions. during thedrying ofthe Aneutralized mass, inasmu'chjas there will be noprejudicial changes in the desired characteristics of the modifiedstarch after it has reached this stage ofthe operation. There l lis nowadded tothe starch product, modi-v ied, neutralized 'and dried, ashereinbefore described, vcasein and an alkali or alkaline material inan'amont suficient, when. ad-

mixed witha suitable-mineral baseto pro-1 .duce a composition which willbe of a'thin flowing Vconsistency, capable4 of being ap-.l

upon thefinished surfacezand which, when ,plied to paper` uniformly,smoothly' and tenaciously,'w1thout leaving brush marksv dried, will bestrongly adhesive to the paper.

In practice, I havetu'sed, With good results, casein in amount equal toby weight ofthe modified starch, and have 'added to the casein, for the.purpose of rendering same soluble, 2% of disodium phosphate. Theseproportions may be varied according to the class of coating required.

In order to make up, the composition ernployed for the coating oflithographers paper, a suitable mineral base may be employed, as forinstance, kaolin, blanc xe,

or the like. In the case of kaolin, 100 lbs. 'may be employed intimatelymixed with 50 lbs. of Water. lbs of the dry modified starch produced inaccorda-nce With the method hereinbefore described, to which has beenadded 10% or more by Weight of finely powdered casein admixed with asuitable With kaolin and Water until the Whole is in a homogeneousunion. The mixture is then strained and is ready for the paper coater,Who may luse additional Water for thinning down purposes, -according to--the /particular character of coating which he Wishes to produce forthe purpose at hand.v Where another mineral' base 1s employed inconjunction with kaolin the'same proportion of modied starch may beusedas if,

kaolin Were alone employed, e., 2 5 lbs. of modified starch to 100 lbs.ofthe total' mineral base employed.

Ifit be desired to use satin White in conjunction vith kaOlin, the satinWhite should first be sized With casein glue. Iv have used with goodresults for sizing satin White about 10% of its Weight of casein glue.The l sized satin White should then be added to the kaolin sized ashereinbefore describedw When, for' special reasons,it is desired to'.make use 'of the fundamental features of my invention, for theproduction of a .com-

position to be immediately applied to the paper, I may proceed directlywith the pro. duction of the coating Without producing the modifiedstarch in a dry state. In ac` coi-dance With this practice, I preferrtointroduce thestarch and the-oxalic acid, in

the'vsame relative ,quantities'in a ,volume ofL Water sufhcient tobringthe starch into sus- -pension, and tothen heat the mixture sum,

ciently'to break up' the starch granules and expose the rbroken granulesat once lto the full action'of the oxalic-acid. .This'is entirelyfeasible on an economical basis, for

4the reason that the mass thus produced [does not require to be driedbefore being put into use; Whereas, for vthe produftion of a dry productit is undesirable to thus break up the starch granules for the reason`that the resulting paste Would4 be difiicult to dry ex-4 cept atconsiderable expense, and under conditions diflicultto effectuallysupervise and determine. v'

lNhen, in the modification of the process referred to, the boiling hasproceeded until a test sample, containing tbe same relative Weightofistarch to Water as in the standard solution hereinbefore specifiedcindicates the desired Viscosity,the necessary amount of ammonia isadded to the vat t`o effect the entire neutralization of the acid orlike modifying agent, ten per cent. (10%) or more by` Weight of finelypowdered casein which has received an addition of some suitable alkalior alkaline material or substance having the power of dissolving casein,as, for instance, 2 per cent. of disodium phosphate, is then mixedvvitha small quantity of Water and brought into solution and thissolution of alkalized casein is added Ato the modified and neutralizedstarch. The resultant mass of modified starch and casein is then readylfor incorporation with the corresponding relative quantityl lofAmineral' base for the final coating composition. The mineral base .inadmixtuqe with the appropriate amount of Water is thereu on=incorporated With the mass of modi ed starch fand casein, and theVcomposition thus produced is ready after straining, lfor use.

In some instances, I prefer to add to thev composition of modifiedstarch and casein, a suitable amount of formaldehyde to give' itWaterproofing properties, and also to guard against decomposition andfermentatiye action, When, for any reason, such action is to beapprehended, as, for example, when the exigencies of manufacture or'usecause it to be kept temporarily (say over night) in the Wet or moiststate.

Having thus described myinvention what I claim is: Y

yl. The method of producing a' composi# tion for use iny paper coating,which comprises modifying a body of starch by the action ofa hydrolyzingagent, neutralizing the modified starch by means of ammonia, andadmixing it with casein, a substance having the powerof dissolvingcasein, and

of the starch being arrested after proceeding so far that the finalcoating composition will have a free flowing consistency and lli strongadhesion rWhen applied as a coating to paper; substantially asdescribed.

'.2. ,The method of producing a composi- P'tion for use inpapercoating,4 whichcomprises modifying a bddyof' starch by the action ofa,solution o f a hydrolyzing agent,

.evaporat ing the solvent,l1neutraliz1ng the modified starch by means ofammonia, and" the power of *tent that when admiXed with water,

admixing' it with casein, a substance having dissolvingcasein, and alarge proportion of a suitable mineral base, t0- gether with water themodification of the starch-being arrested after proceeding .so

far that the final coating composition will have a freelowingconsistency and strong adhesion: when applied as a coating topaper; substantially as described.

3. The. method of' producing a composition for use in paper coating,whichconsists in modifying a body of starch by the. action of a solutionof a-hydrolyzing agent, evaporating the solvent, neutralizing themodified starch by means of ammonia, drying the nmodified neutralizedstarch, and admixing it with casein, a substance havingv the power ofdissolving casein, :and a large proportion of a suitable mineral base,together with water, the Vmodification vof the starch being arrestedafter proceeding so far that the final coating composition will, have afree flowing consistency and strong adhesion y.when ap# plied as acoating described.

4. As a paper coating composition, casein, a 'substance having the powerof dissolving casein, a large proportion ofa suitable mineral base and'starch which has been modied by a hydrol'yzing agent to such an eilit ecomposition will be ,strongly adhesive, of freeowing consistency, andcapable of use without leaving superficial brush marksto paper;substantially as,

' toA 45e. c. o r thereabout, per half minute,

5. As a papercoat'ng composltion, casein, a substance having the powerof dissolving casein, a -large proportion of a suitable mineral base andstarch which has been modied by a hydrolyzing agent to such an tent thatwhen' admixed. with water,

ex'- vthe capable of use free flowing consistency, and

marks without leaving superficial brush composition will be stronglyadhesive, of

when applied as a coating to paper, said composition having been treatedwith formaldehyde; substantially as described.

6. As a paper coating composition, casein,-

a substance havmg the power of dissolving casein, a'large proportion ofa suitable ,mineral ba'sejand'starch which has been modied by a`hydrolyzing agent to such an eX- tentlthat when admixed with nine' partsby' weight ofv water and neutralized with am- Amonia and heated to atemperature suf- -licient to break up its starch granules, it Vwillhave,

cosity ranging from 40 c. c. or thereabout,

as'measured by a burette delivering 58 c. c. .of water per half minute;substantially as described. 2 AIn testimony whereof I aliix my.signature, iii-presence of two witnesses. Y ANDREW A. DUNHAM.

'Witnesses: D.' A. STEVENS,

v ,0.11, Canne.

after cooling to 100 F., a vis?

